1. Field of the Invention
The present invention relates to a metal processing method, and a manufacturing method for a metal mask and a manufacturing method for an organic light emitting panel using the metal processing method. More specifically, the present invention relates to a metal processing method of processing a metal surface, a manufacturing method for a metal mask using the metal processing method, and a manufacturing method for an organic light emitting display device using the metal processing method.
2. Description of the Related Art
In recent years, an image display device using self light emitting elements called organic light emitting diodes (OLED) (hereinafter, referred to as “organic light emitting display device”) has entered the practical stage. Compared to conventional liquid crystal display devices, the organic light emitting display device, using the self light emitting elements, has superior visibility and response speed, and further thinning and power saving may be achieved because an auxiliary lighting device, such as a backlight, is unnecessary.
In the organic light emitting display device, low-molecular organic light emitting layers, which are self light emitting elements, are RGB light emitting layers to constitute a pixel array. In general, those organic light emitting layers are deposited on a glass substrate by vacuum vapor deposition as described in Japanese Patent Application Laid-open No. 2003-68456. The deposited organic light emitting layers have a direct influence on display screen definition. Therefore, forming the organic light emitting layers with stable high precision is one of the important issues in manufacturing an organic light emitting display device in terms of achieving higher resolution of the organic light emitting display device and in terms of improving yields in a manufacturing process for the organic light emitting display device.
High-precision vacuum vapor deposition is achieved under the condition that a metal mask to be used in vacuum vapor deposition is shaped with high precision. Hereinafter, a conventional manufacturing method for a metal mask is described.
FIG. 5 schematically illustrates the conventional manufacturing method for a metal mask 950 in cross-sectional view. As illustrated in FIG. 5, a metal plate 910 serving as a base of the metal mask 950 is first manufactured (Step S801). The metal plate 910 is, for example, a nickel-iron (Ni—Fe) alloy having a thickness of 50 μm. Next, a photoresist liquid is applied to upper and lower surfaces of the metal plate 910 to form photoresist films 920 and 930, respectively (Step S802). Subsequently, pattern exposure and development are performed to remove unnecessary parts of the photoresist films 920 and 930 (Step S803).
Next, the resultant metal plate 910 is immersed in an etchant so that metal portions without the photoresist films 920 and 930 are etched (Step S804) to form holes (Step S805). Finally, the remaining photoresist films 920 and 930 are removed to complete the metal mask 950 (Step S806).